For the first time, a double-blind, placebo controlled clinical trial testing a new therapy for COVID-19, the antiviral drug remdesivir, has produced positive results.

The National Institute of Allergy and Infectious Diseases (NIAID) reported April 29 that preliminary data from the study indicates that patients with advanced COVID-19 symptoms who received remdesivir recovered 31% faster than similar patients who received a placebo.

Specifically, the median time to recovery was 11 days for patients in the treatment group compared to 15 days for patients in the control group. For the purposes of the study, recovery was defined as being well enough for a hospital discharge or to return to normal activity levels. The mortality rate for the treatment group was also lower at 8.0% compared to 11.6% for the placebo group.

The preliminary data is based on results from 460 participants out of 1,063 enrolled in the study.

"I'm cautiously optimistic that the results will look even better with more patient data analyzed," says Elizabeth Hohmann, MD, an infectious disease specialist and principal investigator for the ACTT trial at Massachusetts General Hospital

While the results are significant, the structure of the trial is important as well, as it is the first to employ the double-blinded, placebo-controlled method that is considered the gold standard for proving treatment effectiveness. Earlier reports of promising results from therapeutic trials COVID-19 have been complicated by the lack of a true placebo group.

"It's a blinded study, it shows a positive result and that we’re affecting the course of the illness and maybe mortality," explains Dr. Hohmann. "So that's very exciting."

ACTT began at the University of Nebraska Medical Center in February and now includes 68 sites in the Unites States, Europe and Asia. Mass General was the first center in New England to join the trial and has enrolled about 50 participants. Remdesivir was originally developed by Gilead as a treatment for the Ebola virus, but has not been approved by the FDA for that purpose.

"One of the good and bad points about this study was that it included patients with a wide spectrum of illness,” Dr. Hohmann notes. Some were intubated in the ICU while others were hospitalized and receiving supplemental oxygen but not in intensive care.

She is hoping that a deeper analysis of these patient subgroups will allow investigators understand more about the timing of the treatment and who is most likely to benefit.

Dr. Hohmann says, "The most important question for me is for those people who are sick enough to be in the hospital but only being treated with supplemental oxygen, can we do something to change their disease trajectory?" 

While the results are promising, it will be important to continue testing other potential treatments given the wide spectrum of disease in COVID-19, Dr. Hohmann says. “There may be approaches that are appropriate for people who've reached a certain level of illness and for treating complications."

"If somebody has a blood clot or a stroke or very high markers of certain blood tests, might we want to put that person in a different bucket or pathway? There's so much left to learn and there are many other viable options. Some of those might be added to a drug like this."

More work is also needed to establish how and when clinicians can use remdesivir as a treatment, Hohmann notes. The FDA and Gilead are currently in talks about making the drug available on an emergency use basis.

"There are so many practical things we need to think about now that we have what looks like a positive result." Dr. Hohmann says. "Everyone is on the edge of their chairs, wondering what action the FDA will take and when."